[master / 22.06] docker buildx install breaks alias check

[thaJeztah]

Description

Not sure when this broke (did not yet do a bisect), but I noticed that if the ~/.docker/config.json contains an alias for builder (which happens after running docker buildx install), the CLI is broken;

docker version
not allowed to alias with builtin "buildx" as target

Reproduce

make -f docker.Makefile binary

Without alias installed:

rm ~/.docker/config.json
./build/docker version
Client:
 Version:           22.06.0-beta.0-140-g3dad26ca2.m
 API version:       1.42
 Go version:        go1.19.1
 Git commit:        3dad26ca2
 Built:             Wed Sep 28 22:36:09 2022
 OS/Arch:           darwin/arm64
 Context:           default
...

After running docker buildx install;

./build/docker buildx install

cat ~/.docker/config.json
{
	"auths": {},
	"aliases": {
		"builder": "buildx"
	}
}

./build/docker version
not allowed to alias with builtin "buildx" as target

The error occurs in this part of the code inside processAliases();

cli/cmd/docker/aliases.go

Lines 29 to 31 in c780f7c

	if _, _, err := cmd.Find(strings.Split(v, " ")); err == nil {
	return args, osArgs, errors.Errorf("not allowed to alias with builtin %q as target", v)
	}

Because the cmd.Find("buildx")) returns a cmd. From a quick test the cmd it finds may be the "stub" command we create for plugins; when disabling the buildx plugin (renaming the file), the problem goes away;

mv /usr/local/lib/docker/cli-plugins/docker-buildx /usr/local/lib/docker/cli-plugins/docker-buildx-disabled
 
./build/docker version
Client:
 Version:           22.06.0-beta.0-140-g3dad26ca2.m
 API version:       1.42
 Go version:        go1.19.1
 Git commit:        3dad26ca2
 Built:             Wed Sep 28 22:36:09 2022
 OS/Arch:           darwin/arm64
 Context:           default
...

Expected behavior

No response

docker version

current master (built from https://github.com/docker/cli/commit/3dad26ca2d418092b8c4e01b03d0455d583bec86)

Client:
 Version:           22.06.0-beta.0-140-g3dad26ca2.m
 API version:       1.42
 Go version:        go1.19.1
 Git commit:        3dad26ca2
 Built:             Wed Sep 28 22:36:09 2022
 OS/Arch:           darwin/arm64
 Context:           default

docker info

not relevant

Additional Info

No response

[thaJeztah]

@crazy-max PTAL; perhaps you have an idea how we can detect if a command is a "plugin" or not (haven't looked closely yet; perhaps we have annotations we can use)

[crazy-max]

@thaJeztah I'm not able to repro with #3314 but with latest changes from master yes. I will take a look.

Edit: was able to bissect and it happens since #3429

[thaJeztah]

I have an easy fix for this, but I think it's a partial fix (looking at better fixes that may also help with the performance regression)

Might push the "easy fix" first and fix the rest later

[thaJeztah]

opened #3795 with the "easy" fix